Breakdown voltage enhancement of the p-n junction by self-aligned double diffusion process through a tapered SiO2 implant mask

The low doping region extension at the edge of the junction curvature is implemented with the self-aligned double diffusion process using a tapered SiO/sub 2/ implant mask. The p/sup +/-p-n diodes fabricated with the proposed double diffusion process have relaxed the surface electric field at the junction curvature and increased the breakdown voltage by 140 V, compared with the cylindrical p-n junction. It is also found that the breakdown voltage of the p/sup +/-p-n diodes having the field plate (FP) over the tapered oxide is 500 V, while that of the conventional p-n junction with the FP is 280 V.<>